1. Field of the Invention
The present invention generally relates to semiconductor substrate processing. More specifically, the present invention relates to controlling processes in the manufacture of integrated circuits.
2. Description of the Related Art
Integrated circuits may include more than one million micro-electronic devices (e.g., capacitors, transistors, and the like) that are formed on a substrate (e.g., silicon (Si) wafer) and cooperate to perform various functions within the circuit. Fabrication of the micro-electronic devices may comprise multi-pass processes in which one or more layers of a film stack of the device are repeatedly deposited and selectively etched, thereby forming structures of the devices being fabricated.
To control the multi-pass process, dimensions (i.e. critical dimensions) of the respective elements of the structures are generally measured on a batch of the substrates processed using specific processing equipment (e.g., deposition, etch, or chemical mechanical polishing (CMP) processing equipment, and the like). The results of the measurements are then statistically averaged for that batch of the substrates and used to adjust the processing equipment. Such measurements are typically performed using measuring tools, which are external (i.e., ex-situ measuring tools) to the processing equipment.
This method does not allow compensating for substrate-to-substrate variations of the critical dimensions within the batch of the substrates. Manufacturing variables of different processes comprising a pass of the multi-pass process may combine and broaden distribution of the critical dimensions of the elements of the structures beyond allowable ranges. As such, some structures and devices may be defective.
Therefore, there is a need in the art for an improved method for controlling a multi-pass process of fabricating integrated devices.